Cryolite
Yang H, Ghose S, Hatch D M
Physics and Chemistry of Minerals 19 (1993) 528-544
Ferroelastic phase transition in cryolite, Na3AlF6, a mixed
fluoride perovskite: high temperature single crystal X-ray
diffraction study and symmetry analysis of the transition mechanism
Sample: T = 573 K
_database_code_amcsd 0007742
5.4766 5.6227 7.8461 90 90.089 90 P2_1/n
atom      x     y     z B(1,1) B(2,2) B(3,3)  B(1,2)  B(1,3)  B(2,3)
Al        0     0     0 .01613 .01573 .01457 -.00051 -.00011 -.00040
Na1       0     0    .5 .02796 .02697 .02514 -.00450 -.00108  .00241
Na2  -.0096 .4542 .2519 .03989 .03667 .04245 -.00621 -.00067  .00024
F1    .0967 .0418 .2182 .04174 .04682 .01739  .00146 -.00569 -.00507
F2    .2299 .3264 .5433 .02909 .03345 .04014 -.01292  .00537 -.00037
F3    .1640 .2680 .9413 .03321 .02779 .04851 -.01068 -.00001  .00770